Annie Shaw emerges from the garden she instigated on a former trash-strewn vacant spot on Pennsylvania Avenue.

Photo: Brant Ward, The Chronicle

Annie Shaw emerges from the garden she instigated on a former...

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Annie Shaw with her newest creation, a garden in another former patch of rubble, this one on Pennsylvania Avenue.

Photo: Brant Ward, The Chronicle

Annie Shaw with her newest creation, a garden in another former...

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A v-shaped piece of land that Potrero Hill resident Annie Shaw transformed, as seen in the 1973 Clint Eastwood movie, Magnum Force.

Photo: Courtesy Of Annie Shaw

A v-shaped piece of land that Potrero Hill resident Annie Shaw...

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A v-shaped piece of land that Potrero Hill resident Annie Shaw transformed, as seen in the 1973 Clint Eastwood movie, Magnum Force.

Photo: Courtesy Of Annie Shaw

A v-shaped piece of land that Potrero Hill resident Annie Shaw...

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A before image of the v-shaped piece of land tranformed by Potrero Hill resident Annie Shaw.

Photo: Courtesy Annie Shaw, Courtesy Annie Shaw

A before image of the v-shaped piece of land tranformed by Potrero...

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A before image of the v-shaped piece of land tranformed by Potrero Hill resident Annie Shaw.

Photo: Courtesy Annie Shaw, Courtesy Annie Shaw

A before image of the v-shaped piece of land tranformed by Potrero...

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Yucca filamentosa colorguard, one of Annie Shaw's favorite plantings along Pennsylvania Avenue. Annie Shaw has created two gardens out of rubble on Pennsylvania Avenue in San Francisco, Calif. The parks, once covered with concrete and homeless encampments, are now in bloom Tuesday February 12, 2013.

Photo: Brant Ward, The Chronicle

Yucca filamentosa colorguard, one of Annie Shaw's favorite...

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A geranium from the garden crowds a graffiti marked caution sign near the highway 280 offramp. Annie Shaw has created two gardens out of rubble on Pennsylvania Avenue in San Francisco, Calif. The parks, once covered with concrete and homeless encampments, are now in bloom Tuesday February 12, 2013.

Photo: Brant Ward, The Chronicle

A geranium from the garden crowds a graffiti marked caution sign...

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Annie Shaw had to deal with City Hall and CalTrans to develop the areas. Annie Shaw has created two gardens out of rubble on Pennsylvania Avenue in San Francisco, Calif. The parks, once covered with concrete and homeless encampments, are now in bloom Tuesday February 12, 2013.

Photo: Brant Ward, The Chronicle

Annie Shaw had to deal with City Hall and CalTrans to develop the...

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Hundreds of empty plant containers sit in the rear of a garden, a testament to the numbers of plants required. Annie Shaw has created two gardens out of rubble on Pennsylvania Avenue in San Francisco, Calif. The parks, once covered with concrete and homeless encampments, are now in bloom Tuesday February 12, 2013.

Photo: Brant Ward, The Chronicle

Hundreds of empty plant containers sit in the rear of a garden, a...

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Arum Ahn (left), Annie Shaw (center) and Emily Gogol visit the Pennsylvania Avenue Garden in San Francisco, Calif., on Friday, July 16, 2010. The three Potrero Hill neighbors organized a community effort to start up and maintain the garden which is located next to the Mariposa Street off-ramp from Interstate 280.

Photo: Paul Chinn, The Chronicle

Arum Ahn (left), Annie Shaw (center) and Emily Gogol visit the...

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Annie Shaw developed a fondness for Yucca plants and used them in her gardens. Annie Shaw has created two gardens out of rubble on Pennsylvania Avenue in San Francisco, Calif. The parks, once covered with concrete and homeless encampments, are now in bloom Tuesday February 12, 2013.

Photo: Brant Ward, The Chronicle

Annie Shaw developed a fondness for Yucca plants and used them in...

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Neighbor Susan Olk and her dog Hanna enjoy the garden in the 200 block of Pennsylvania Avenue. Annie Shaw has created two gardens out of rubble on Pennsylvania Avenue in San Francisco, Calif. The parks, once covered with concrete and homeless encampments, are now in bloom Tuesday February 12, 2013.

Photo: Brant Ward, The Chronicle

Neighbor Susan Olk and her dog Hanna enjoy the garden in the 200...

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Neighbor Susan Olk and her dog Hanna enjoy a walk in the southern most garden near the highway 280 exit. Annie Shaw has created two gardens out of rubble on Pennsylvania Avenue in San Francisco, Calif. The parks, once covered with concrete and homeless encampments, are now in bloom Tuesday February 12, 2013.

Photo: Brant Ward, The Chronicle

Neighbor Susan Olk and her dog Hanna enjoy a walk in the southern...

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Arum Ahn (left) and Annie Shaw tend to the Pennsylvania Avenue Garden on Potrero Hill in San Francisco, Calif., on Friday, July 16, 2010. The two Potrero Hill residents teamed up with another neighbor Emily Gogol to organize and maintain the garden.

Annie Shaw was living a typical San Francisco existence: She worked as a Web designer, liked her Potrero Hill apartment and was happy not knowing any of her neighbors.

Then one day her boyfriend, an art director, mentioned that he'd love to move so they could have a house with a garden.

Shaw looked across the street and pluckily declared, "We could make a garden out of that!"

That was in 2008, and the land Shaw eyed was woeful, dotted with discarded mattresses and tires, car batteries, garbage, and the detritus of the homeless. And it abutted a freeway off-ramp.

No matter. Shaw, who is from North Wales and has a cheerful disposition that belies a don't-mess-with-me will, rolled up her sleeves, pointed her car headlights at the blighted land, and began her after-hours cleaning and digging.

Five years later, after staring down various city and state officials, securing community grants, and rallying the locals, Shaw has transformed not just one scrap of Potrero Hill dirt into an urban oasis, but two. Over three weekends in January and February, she and a team of 70 volunteers put in 23 trees, 800 plants, a rainwater permeable sidewalk and parking wheel stops made from Sonoma fieldstone boulders. The two gardens are both situated on Pennsylvania Avenue, off the southbound 280 Mariposa Street exit.

"I believe in what she's doing, and I've supported her on both projects," said Nuru, a landscape architect by training. "I'd drive by, and there she was out working. San Francisco needs more Annie Shaws."

Shaw, 41, demurred and said, "It started as a really selfish thing. I wanted to have a garden."

Caltrans land

The first garden project, in the 200 block of Pennsylvania Avenue, is owned by Caltrans and had been overlooked for decades. (The V-shaped, weed-strewn lot made an appearance in the 1973 Clint Eastwood police film "Magnum Force.")

"I had never gardened before," Shaw said. "I started by planting some flowers, and I just kept plugging away at it."

Smiling, she added, "I take on big projects, and naivete gets me though the first six months."

Within those first six months, Shaw was informed by a friend who worked at Caltrans that other Caltrans officials were talking about her and considered her a "liability."

When a meeting was called, Shaw decided she had better tell her neighbors what was going on and seek their support. She had started a blog (psgsf.org), and quickly discovered that many in the neighborhood were already closely following her efforts.

Shaw arrived at the Caltrans meeting with a petition of support signed by 250 residents of Potrero Hill.

"By this time, I had kind of gone to town," Shaw said, walking through what is now known as the Pennsylvania Garden. "I had gone from planting a few flowers to doing shrubs and paths, archways and sprinklers."

At the meeting, attended by seven Caltrans representatives, Shaw listened as she was told she couldn't have a bench (homeless people would camp out there), she couldn't have twig borders (someone could trip), and she couldn't have any number of things she'd already done.

At this point, Gary Brickley, who owns a film and video production company adjacent to the nascent garden, stepped in and told the state officials that locals really liked what Shaw already had.

Many benefits

"It's great for the neighborhood, great for the environment, and great for the birds, bees, insects and animals," Brickley said, as Shaw - who had already spent $5,000 of her own money - made it clear in her firm-but-smiling way that she was just getting warmed up.

Shaw soon attracted the help of a seasoned grant writer, Emily Gogol, and the support of Nuru, with the Department of Public Works. Nuru said, "Caltrans appreciated what Annie was doing, but the work was happening on their property without any approval. We all wanted to figure out how to make it legit, so we got Annie the permits she needed."

After planting thousands of species - the most prevalent being tough succulents like aloe, yucca and various cacti, as well as lavender, grasses, Bush poppy and daffodils, a flower of Wales - Shaw began to eye another blighted area down the street.

Grants came through

She and her boyfriend, Matt Petty (a former Chronicle art director), had moved a few blocks down, and her view lacked one thing: a garden. She drew up plans for a second project, and she and Gogol were able to secure more than $137,000 in community grants and individual donations, with the funds going to both projects.

"I thought, 'This project can't be worse than the first one; it's going to be a slam dunk,' " Shaw said. Walking down Pennsylvania Street, she pointed out the railroad tracks and Mission Bay in the distance.

"The mistake I made," she said, "is that I openly talked about this before I started, and we had to do all sorts of landscape architect tests. It was so much back and forth and red tape. It was a bureaucratic nightmare, and we wanted to give up so many times. It took two and a half years before we could finally break ground. But we had the support of Nuru, and I just said, 'Dammit, I'll have my trees. I'll have my plants. I'm going to do this. Let's see who's more stubborn.' "

Shaw surveyed the newly planted area, to be called the Pennsylvania Railroad Garden, with its rainwater permeable sidewalk, dozens of trees and hundreds of plants, with its wheel stops made from boulders, and said, "It's never done. I'm already thinking about what we need to do next." Before heading back up the hill, she stopped to take a whiff of a new peppermint acacia tree.

"This has been pretty much my obsession," she allowed. "One of the interesting things to come out of it is that I now know my neighbors. I was happy being anonymous, but I feel a strong sense of community. It's a much richer feeling."

Returning to the Pennsylvania Garden adjacent to the Mariposa Street off-ramp, she stood under an archway covered with cape sweet pea, a South African vine that she noted smells like grape Kool-Aid.

"Hummingbirds!" she exclaimed, looking into the garden. "And do you hear the mockingbirds and see all of the bees?"

Smiling proudly, she said, "This used to be flies and rats, and now it's birds and bees."

Asked whether she has her sights set on another guerrilla gardening project, her eyes lit up.

"Any full sun spot, small enough to be planted in one or two nights, in a sad state so the transformation is significant," she said. "And in a location where many people can enjoy it."